New mechanism of defect production in metals: A molecular-dynamics study of interstitial-dislocation-loop formation in high-energy displacement cascades

We present molecular-dynamics computer-simulation studies of 25-keV displacement cascades in Cu at low temperature. We observe the splitting of a cascade into subcascades and for the first time show by molecular dynamics that cascades in metals may lead to the formation of both vacancy and interstitial dislocation loops. We propose a new mechanism of defect production based on interstitial prismatic dislocation-loop formation and discuss its consequences regarding the primary state of damage in irradiated metals.